1. Field of the Invention
This invention relates to a structural, composite armor for absorbing kinetic energy transferred upon impact by, and limiting penetration by, incident projectiles and a method of manufacturing the composite armor.
2. Background Art
Conventional armor for vehicles calls for the deployment of rigid plates and/or panels that are made from such materials as metallics, ceramics, composites, and the like. Ideally, materials that are used to protect vehicles and their components are light in weight, while affording protection against an oncoming projectile. In operational use, the armor influences an incident projectile so that penetration through the armor plating is avoided. Traditionally, such protective structures prevent the penetration of fragments and debris from the projectile and the material from which the armor is made through any openings created in the rear portions of the armor.
The transfer of kinetic energy occurs through a combination of mechanisms. One occurs where the armor has sufficient thickness and its material is selected so as to impede and present an impenetrable barrier to the incoming projectile. Such an approach, however, involves the adverse consequences of bulk and weight. Another mechanism occurs where the incident projectile is re-routed by eroding, fracturing, or rotating it. A third mechanism involves deforming or bending the incoming projectile so that its impact area is enlarged and the consequent force per unit area is thus diminished.
Such protection mechanisms, however, have yielded mixed results, and the quest for an ideal armor platexe2x80x94one which has the attributes of rigidity, strength, low density, impact resistance, and ease and favorable cost of manufacturingxe2x80x94continues.
It is known that ceramic tiles bonded to such materials as KEVLAR(copyright) as a backing material can be effective against certain armor-piercing bullets. In its broad sense, the term xe2x80x9cceramicxe2x80x9d includes certain inorganic materials, except metals and metal alloys. Ceramics may range in form from a vitreous glass to a dense polycrystalline substance. Typically, ballistic ceramics (armor grade ceramics) are brittle and exhibit nearly linear stress-strain curves. Such materials are often characterized by a compressive strength that exceeds tensile strength. Armor grade ceramics include aluminum oxide (Al2O3), silicon carbide (SiC), silicon nitride (SiN), boron carbide (B4C), and others.
The hardness of ceramics diminishes an incident projectile""s penetration by initiating its break-up. After shattering, residual projectile fragments are ideally constrained by the armor-backing materials (debris/spall liners). Thus, the prior art includes ceramic layers that deflect and break incoming projectiles, while the backing materials constrain the residual projectile and fragments.
Illustrative of the prior art are U.S. Pat. Nos. 5,763,813 and 6,112,635 which respectively are assigned to Kibbutz Kfar Etzion and Mofet Etzion. The ""813 patent discloses a composite armor material with a panel that consists essentially of a single internal layer of ceramic pellets that are directly bound and retained by a solidified material in superimposed rows. A majority of the pellets is in contact with at least four adjacent pellets. Such approaches lead to inconsistencies in the location of pellet arrays, especially around the edges of the panel and points at which the panel is attached to a substrate which is protected by the armor plate. As a consequence of localized weak points, some anisotropy results. Such approaches also leave opportunities for improvement in multi-hit performance.
It is also known from UK Patent Number 1,142,689, published on Feb. 12, 1969, that other forms of composite light weight armor plate can be effective. That reference discloses energy-dissipating spheres which are embedded in a plastic matrix. Id., ll. 85-90. U.S. Pat. No. 6,112,635 discloses a composite armor plate with a single internal layer of high density ceramic pellets that are retained in plate form by a solidified material. Other prior art references noted during an investigation in connection with the present invention include these United States patents: U.S. Pat. No. 3,577,836 Tamura; U.S. Pat. No. 3,705,558 McDougal et al.; U.S. Pat. No. 4,198,454 Norton; U.S. Pat. No. 4,404,889 Miguel; U.S. Pat. No. 4,529,640 Brown et al.; U.S. Pat. No. 4,880,681 Price et al.; U.S. Pat. No. 5,221,807 Vives; U.S. Pat. No. 5,310,592 Baker et al.; U.S. Pat. No. 5,349,893 Dunn; and U.S. Pat. No. 6,030,483 Wilson.
It is an object of the invention to provide a structural composite armor that will present to an incident projectile a barrier to entry of any fracture debris through a rear surface of the armor.
More specifically, an object of the invention is to provide a composite armor including a cellular structure with polygonal openings and oppositely facing sides between which the openings extend. Inserts are received by the openings. To close the openings, a pair of sheets are secured to the oppositely facing sides of the cellular structure.
Preferred modes of practicing the invention include its method of making.
The objects, features, and advantages of the present invention are readily apparent from the following detailed description of the best modes for carrying out the invention when taken in connection with the accompanying drawings.